The present invention relates to a clamp for holding an elongated object or component, such as a pipe or a wire harness, in order to fix the object to a substrate or workpiece, such as an automobile body. In particular, the present invention relates to an antivibration clamp for an elongated object, designed to prevent vibration transmission to or from the object.
Japanese Utility Model Laid-Open No. 4-44581 (Publication 1) discloses a clamp for an elongated object, e.g., a pipe or the like, designed to prevent occurrence of fluttering noise caused by vibrations. This clamp comprises a base and an object-holding portion supported by the base. The object-holding portion includes a curved wall defining a recess for receiving an object therein, and a resilient holding finger extending obliquely from the top of the curved wall, or its vicinity, toward the recess of the curved wall to press against the outer surface of the object. The inner wall surface of the curved wall is coated with a soft buffering resin material. The soft buffering resin material absorbs fluttering noise of the object held in the curved wall.
Japanese Utility Model Laid-Open No. 4-75289 (Publication 2) discloses an antivibration clamp for an elongated object, e.g., a pipe or the like, designed to prevent vibration transmission to or from the object. This antivibration clamp includes an object holding portion composed of a pair of clamp members openably connected with one another by a thin hinge. Opposed surfaces of the clamp members are provided with an antivibration portion made of noise isolating/absorbing soft resin material to clamp an object between the opposed antivibration portions to avoid the object being pulled-out. The antivibration portions cover the outer surface of the object to obtain vibration-proof effect.
Japanese Patent Laid-Open No. 9-79432 (Publication 3) discloses an improvement of the clamp disclosed in Publication 1. Soft buffering resin material provided on the inner wall surface of the curved wall holds an object while preventing the object from being displaced in the axial direction. An aim of the improvement is to reduce the risk of a strong force applied in the axial direction of the object causing peeling of the soft buffering resin material. Specifically, the clamp of Publication 3 is directed to fixing the soft buffering resin material to the curved wall in such a manner that the soft buffering resin material extends along opposite side edges of the recess of the curved wall in a C-shape, to clasp the side edges so as to prevent the peeling.
Japanese Patent Laid-Open No. 10-248145 (Publication 4) discloses a cord clamp formed with a plurality of cord-holding portions and intended to facilitate an operation of inserting a cord therein, and to prevent a returning force of the cord-holding portions from deteriorating under a high temperature. This cord clamp is formed with a gap between the adjacent cord-holding portions to isolate them from one another, and a resilient member is inserted into the gap. The resiliency of the resilient member in the gap is utilized to prevent the returning force of the cord-holding portions from deteriorating in a high temperature environment, such as an engine compartment.
Japanese Patent Laid-Open No. 2000-230674 (Publication 5) discloses a pipe clamp comprising an automobile-body connection portion or base, a pipe binding portion or pipe-holding portion, separated from the base, and a coupling portion made of a soft material and embedded between the automobile-body connection portion and the pipe-binding portion through a two-color molding process. The soft coupling portion interposed between the automobile-body connection portion and the pipe-binding portion is utilized to absorb vibrations of the pipe held by the pipe-binding portion so as to prevent vibrations from being transmitted to the automobile-body connection portion.
While the clamp disclosed in Publication 1 (Japanese Utility Model Laid-Open No. 4-44581) has an antivibration function based on the soft buffering (antivibration) resin material covering an object held in the curved wall, a higher antivibration effect can be obtained only by increasing the thickness of the antivibration resin material. However, the antivibration resin material increased in thickness causes a problem of deterioration in the object holding force due to resulting increased softness or flexibility, which is likely to cause wobbling movements of the object in the curved wall. Further, as pointed out in Publication 3 (Japanese Patent Laid-Open No. 9-79432), the antivibration resin material tends to be peeled by a strong force applied in the axial direction of the object.
As to the clamp disclosed in Publication 2 (Japanese Utility Model Laid-Open No. 4-75289), a higher antivibration effect can be obtained only by increasing the thickness of the antivibration resin material, and the soft antivibration resin material increased in thickness is likely to cause wobbling movements of an object in the curved wall, similarly to the clamp in Publication 1. Further, because the object-holding portion is composed of the pair of clamp members openably connected with one another by the thin hinge, undesirable labor and time are required for swingably moving one of the clamp members about the hinge to open the object-holding portion, inserting an object into the holding portion, and then closing the clamp member.
While Publication 3 (Japanese Patent Laid-Open No. 9-79432) is intended to prevent peeling of the soft buffering resin material, it is difficult to obtain a sufficient antivibration effect. If the thickness of the soft buffering resin material is increased to obtain a sufficiently enhanced antivibration effect, the holding force will be likely to deteriorate, as with the clamp in Publication 1.
The cord clamp in Publication 4 is intended to prevent the returning force of the cord-holding portions from deteriorating under a high temperature. For this purpose, the resilient member is inserted into the gap between the adjacent cord-holding portions, and the resiliency of the resilient member is utilized to maintain the returning force of the cord-holding portion even if the body of the cord-holding portion has a returning force that deteriorates at a high temperature. This cord clamp is neither designed for the purpose of antivibration, nor has it a sufficient antivibration function. Further, the cord clamp in Publication 4 is devoid of a resilient holding finger extending obliquely from the top of the curved wall of the cord-holding portion toward the recess of the curved wall so as to press against the outer surface of the elongated object to prevent pullout of an object held in the cord-holding portion. Publication 4 does not include any suggestion of absorbing vibrations acting from an object to a resilient holding finger.
In the pipe clamp in Publication 5, a coupling portion made of a soft material is provided between the pipe-binding portion for holding a pipe and the automobile-body connection portion to be fixed to an automobile body. Thus, a fixing force between the pipe held by the pipe-binding portion and the automobile-body connection portion is likely to deteriorate.